An application can be written to be executed by a specific hardware or software. For example an application for one operating system may not execute properly on another operating system. To execute an application on a system that the application is not written for may be done with a virtualizer. A virtualizer can create an environment for the application that appears to the application as the hardware or software that the application was written to execute on. The virtualizer may provide different hardware or software services that can be invoked by the application.